ECMAScript 4 Regular Expression Grammar

ECMAScript 4 Netscape Proposal

Formal Description

Regular Expression Grammar

Monday, June 9, 2003

This LR(1) grammar describes the regular expression syntax of the ECMAScript 4 proposal. See also the description of the grammar notation.

This document is also available as a Word RTF file.

Unicode Character Classes

UnicodeCharacter ⇒ Any Unicode character

UnicodeAlphanumeric ⇒ Any Unicode alphabetic or decimal digit character (includes ASCII 0-9, A-Z, and a-z)

LineTerminator ⇒ «LF» | «CR» | «u0085» | «u2028» | «u2029»

Regular Expression Definitions

Regular Expression Patterns

RegularExpressionPattern ⇒ Disjunction

Disjunctions

Disjunction ⇒

Alternative

| Alternative | Disjunction

Alternatives

Alternative ⇒

«empty»

| Alternative Term

Terms

Term ⇒

Assertion

| Atom

| Atom Quantifier

Quantifier ⇒

QuantifierPrefix

| QuantifierPrefix ?

QuantifierPrefix ⇒

*

| +

| ?

| { DecimalDigits }

| { DecimalDigits , }

| { DecimalDigits , DecimalDigits }

DecimalDigits ⇒

DecimalDigit

| DecimalDigits DecimalDigit

DecimalDigit ⇒ 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

Assertions

Assertion ⇒

^

| $

| \ b

| \ B

Atoms

Atom ⇒

PatternCharacter

| .

| NullEscape

| \ AtomEscape

| CharacterClass

| ( Disjunction )

| ( ? : Disjunction )

| ( ? = Disjunction )

| ( ? ! Disjunction )

PatternCharacter ⇒ UnicodeCharacter except ^ | $ | \ | . | * | + | ? | ( | ) | [ | ] | { | } | |

Escapes

NullEscape ⇒ \ _

AtomEscape ⇒

DecimalEscape

| CharacterEscape

| CharacterClassEscape

CharacterEscape ⇒

ControlEscape

| c ControlLetter

| HexEscape

| IdentityEscape

ControlLetter ⇒

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

| a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z

IdentityEscape ⇒ UnicodeCharacter except _ | UnicodeAlphanumeric

ControlEscape ⇒

f

| n

| r

| t

| v